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. 7 c. w. PLACE AUTOMATIC SWITCHING EQUIPMENT I Filed Sept, 15. 1922 2 Sheets-She l lnvento'v: Cl auoLe W. Piace His trnea Patented Oct. 18, 1927.

UNITED sTArEs PATENT OF I E- CLAUDE W. PLACE, LA GRANGE, ILLINOIS, ACSIGNOB TO GENERAL ELECTRIC COM- PANY, A CORPORATION OF REV?" YORK.

AUTOMATIC SWITCHING EQ UIPMEN'I.

My invention relatesto automatic switching equipments and particularly to autoor are overloaded, and that other sources serve as emergency sources, and supply current only in case one of the other sources fails. at

One object of my invention is to provide a new and improved automatic switching equipment which is arranged to control the connections between a plurality of sources of current and a distribution system in such manner that the sources are arranged to be connected and disconnected from the dlstribution system in accordance with the condi- "tion of the respective sources. A

my invention 1s to pr'o- I Another object of vide an automatic switching equipment whichis arranged to control the connections between a plurality of sources of current and a distribution system so that one of the sources is connected to the distribution system whenever it is energized so that another of said sources is connected to the distribution system whenever itis energized and said one of said sources is either deenergized.

any suitable type. For the purpose; of this description, it will be assumed that the" ci ror overloaded, and sothat a third of said sources is connected to the distribution system whenever it is energized and both of said first and second mentioned sources are deenerg'ized or either of said sources is deener-' between a plurality of sources of current and a. distribution system so that under certaln.

load conditions on the distribution system one of the sources supplies current to all of the load connected to the distribution sys;

tem and under other load conditions said one source supplies currentonly'to a portion ,nating current systems.

circuit breakers, F,; G, .H,

Application filed September 15, 1922. seriaino. 588,469. I

of the load and another source supplies current to another portion of the load.

My invention will be better, understood from the following description taken in connection with the accompanying drawings and its scope will be pointedout in the appended claims. i .L, In the accompanying drawing, Figs. 1 and'2 show diagrammatically. an electric system embodying my invention, and F ig. 3

shows a modification of a portion of the system shown in Figs. 1 and 2. v Referring to Figs. 1' and 2 of the accompanyingdrawings, A, B and C each represents a source of current, such as an alternating current supply circuit, which is arranged tobe connected to a distribution'systerm which may comprise a pluralityo'f distribution circuits .such' as the two feeders D and E. In order to simplify the drawing, single phase alternating current sources are shown but 1t is to be'understoodthat imy inventionis not limited to any particular number of phases and that it is applicable to direct current systems as well as to alter- As showni'ntlie drawing the sourceA is arranged to .be connected directly to [the feeder D by a circuit breaker F and the source B' is arranged to be connected directly tothe. feeder E by a circuit breaker G. The

feeders D and E are arranged to be connected together by circuit breakcrs'H and J and the source C is arranged to be connectedto the feeder D by the circuit breakers K'and J ,andto the 'feeder E by the circuit breakers K and H. The circuit breakers'may be of cuit breakers are of the well known latchedin type which are held in their; closed p 0 which, when energized, closes the breaker,

a trip I coil 31 which, when energized, re-

leases, the latch which holds. the circuit" breaker closed, auxiliarycontacts, a, af etc.

which are closed when the breaker isclosed and; auxiliary. contacts 6; 6 etc. which are. closed when the breakeris openl i The-circuits ofthe coils 3;O-.and of the I J and K are opened and closed mil sasses difierent conditions of the sources A, B and Gand the 'feeders'D' so that under different conditions said sources are connected to said feeders. in different combinatlons. The source A .is'the preferred source, and is arranged to be connected to the feederD by the circuit breaker F Whenever source A is energized. l/Vhen the load conditions on both feeders are such that one source can supply all the load, the source A- is also arranged ,to be connected to the feeder E by the circuit hreak'ers and J. In case the load conditiens are sueh that one "source earinot supply the total load then the source A isjar'ranged to supply only the feeder D d, the supplementary source. B, if enermed; is arranged to be connected to the ieder E by the circuit breaker G. 'If-the G; Hand J If, however; both ofthe sources A and B are notenergized, the emergency sourceC is arranged to'be connected to both f feeders the circuit breakers K, H and J the load conditions are such that one sourc c annot supply the total load and the source A is notenergized, the supplementary source is connected to the feeder E by the circuit breaker G and the emergency source C is co nnec ted to the feeder D by the circuit b eaker-sigma J. H, however the preferred source A and the supplementary 'sp yce are both not energized, the supplementary source'B is connected to bot-h feeders 'bythecircuit breakers G, H and If,v

l dvvever; preferred source and the supplementary source Bare not energiz e d,'

the emergency source C is connected to both feeders by the circuit breakers K, H and? i l is hed in'response to either the energisat on or deenergization of one or more of the sources.

or co trolling the circuits of the closing coils 39 and theftrip coils 3 1 of thecircuit breakers F, GQH, J andK so that the proper coils are energizedin the proper sequence when ehange i s being made in the connections between the sources A, B and C and the feeders D and a controller 42 is proyidedy This controller comprises stationary contacts and 'movable segments which are arranged to interconnect the stationary contacts" in the proper sequence as the controller moves The aboye'connections are arranged to be from one'position to another. Any other suitable means however may be used for controlling the sequence in which the coils are energized and deenergized. T he controller 42 may be driven by any suitable means such as an electric motor 43 which may be connected to any suitable source such las'a control circuit 44, 45,

The fixed contacts of the controller 42 are numbered 1 to 28',inclusive and in order to make it cay to trace the circuits through these contacts,- the conductorspermanently connected to these contacts and the relays '42 is arranged to stop in siX different positions designated by the Roman numerals I to VI inclusive. The horizontal broken lines indicate the positions of the stationarycont'acts on the segments of the controller in they different stopping positions.

-The controller-stops in position I if the ci cuit breakers F and G are closed, the sourccsA and B are energized, and the load connected to the distribution system exceeds a predetermined value. The controller stops in position II if the circuit breakers F; K and H are closed, the sources A and C are energized and'tlie source B is deenergized. and the load connected to the distribution system exceeds a predetermined value. The controller stops in position III if thecircuit breakers G, K and J are closed, the circuit breaker F'is open, the sources B and G are energized the source Ais deenergized and. the load connected to the distribution system exceeds a predetermined value. The controller stops in position IV if the circuit breakers F, H and J are closed, the source A 1s=energized, and the load on the source A does'not exceed a -1 )rcdetermined value Whileeither of the sources B and C are energized. The controller stops in position V when the circuit breakers G. H and dare closed, the source B isenergized, the source A is deenergized and the load on the sourceB does not exceed a predetermined amount While the source C is energized. The controller stops in position VI it all the sources are deenergized and also if only the source C is energized and the circuit breakers K, H and "J are closed v i'roin one'stopping position toanother and the proper connections between the sources and the feeders arceiiected in accordance with predetern'iined conditions ot the sources'and of the distribution system. The particular conditions for controlling the operation of the'controller and of the circuit breakers 1n the arrangement shown in the [lIZLWlIlfZ are the voltages of the sources and and thesources A and B are provided with the overload relays 39and 40," respectively.

The voltage relays 32, 33 and 34' are arranged to close theircontacts a, 0,6, etc. (alternate letters of the alphabet) when the voltages of the respective sources exceed predetermined values and to close their auxiliary contacts 2), (Z, f, etc. when thevoltages of the respective sources are below prededescribed.

termined values. The underload relay is arranged to close its contact 7) and the underload relay 37 is arranged to close its contacts b, b when the currents supplied by the respective sources A and G are less than predetermined values. The overload relays 39 and are arranged to close their contacts (I, when the currents supplied by the respectivecircuits exceedpredetermined values.

The circuits of the control relays 2, 5, 8,

10, 12, 14,16,23, 25 and 28 are controlled by the contacts of the controller, and the contacts of the voltage, underload and overload relays, and the auxiliary contacts on the circuit breakers in a manner hereinafter Each ofthe control relays 2, 5,

8. 10, 22, 25 and 28. when energized, coin- -pletes the circuit ofthe driving motor 43 of the controller across the control circuit The control relays 12, 14 and lti, whenenergized, complete the circuits of the trip coils 31 of the circuit breakers Gr, K and F. respectively. across the control circuit 4 l-45. The circuits of the trip coils 31 of -thecircuit breakers'G. K and F are also HT.

ranged to be completed by contacts .of-the voltage relays 33, 34 and .32 respectively.

When the source A is deenergized'the cur.,

rent of the trip coil-31 of the circuit breaker F is completed, if the circuit. breaker is closed, by means of the auxiliary contacts a on the circuit breaker, conductor 66 and contactsj of the voltage relay. 32. YVhen the source B is deenergized the circuit of the trip coil-3510f the circuit breaker G is completed, if the circuit breaker is closed,

' bycineans of the auxiliary contacts a on the pleted i-Jzqthe circuit breaker isclosechby circuit breaker G, conductor 65, andcontacts j of thevoltage relay 33. \Vhen the source C isdeenergized the circuit of the trip coil 3l ofthe circuit breaker K is commeans of the auxiliarycontacts u on the circuit breaker K, conductor 67 and contacts cl of the voltage relay 34. y Y

The operation of the system shown will be described by assuming thatthe controller is in position V I, and'then describing how the cont-roller is moved froin this position in response to different conditions of the sources, how different conditions of the sources cause the controller to stop in its different stopping positions, and how the move ment of the controller from one position to ,another efi'ects the opening and closing'of the circuit breakers in the proper sequence.

In position VI of the controller the seg- Inents on the controller 'connecttogether the contacts 2 and 3, the contacts 5 and 6,'the

contacts 8 and 9 and the contacts 27 and 28. As heretofore described, the-contacts 2, 5, 8 and 28 are connected'to the control bus by means of the'conductors 2, 5, 8 and 28, respectively which have connected in series therewith the operating coils of the control relays 2, 5, 8 and 28 respectively.

The conductor 3, which is connected toxthe contact 3 of the controller, is arranged to be connected to the control conductor 44: by

means of the auxiliary contact I)" on the circuit breaker K, the conductor and the contactse of the voltage'relay 34: which is connected across the emergency source C.

" Therefore the circuit through the conductors 2 and 3 is completed in position VI of the controller when the source C is energized and the circuit breaker K is opensothat the control relay 2is energized. '"As heretofore described the energization of the control re lay 2 connects the inotor 43 across the supply circuit 44, 4 5. The segments on thecontroller are arranged to connect together the contacts 2 and'3 while thc controller is in position VI' and until it reaches position I. Therefore the energization of the control relay 2 under the aboveconditions effects" the movement of thecontroller from positionVI to position I." 1 f The conductor 6, which is connected to the contact 6 ofthe controller, has two branches, one of which is'arranged to be'connected to the control conductorl l by means of the contacts 9 of the voltage relay 33 connected acrossthe source B, conductor tih'and the ]lay '5 is therefore-completed injposition VI of the controller when the source Bis energized and either the circuit breaker G is open or the source 0 is energized and the source B is overloaded. The segments on theconutroller are arranged to connect together the contacts 5 and 6 while the controller is in positions V and VI and until it reaches-pofition I. Therefore theenergization of the control relay 5 under the above conditions eifects the movement of the controllerfrom position VI to positionl.

The conductor 9, which is connected to the contact 9 of the controller, has two branches. One of these branches is arranged to be connected to the control conductor 44 by means of the contact 6 of the voltage relay 33, conductor 52, either the auxiliary contacts I) on the circuit breaker F or the auxiliary contactsb on the circuit breaker G which are connected in multiple, conductor '51 and contacts a of the voltage relay 32.

The other-branch of the conductor 9 is arranged to be connected to the control con- .dnctor44 by means of the contacts 7 of the voltage relay 33, conductor 51 andcontacts aof the voltage relay 32. It is therefore evi dent that the circuit through the control re lay 8 is completed in position VI of the controller either when both of the sources A land B are energized and either one, of the circu t breakers F, G is open or when the source A 1s energized and the source Bis deenergized. The segments on thecontroller are. arranged to connecttogether the contacts 8 and 9 while the controller is in positions V, VI and I and until it reaches position II. Therefore the energization of the .controlrelay under the above conditions of! .fect-s the movement otthe 1 controller from position VI to position II.

The conductor'27, which isconnected to the contact 27 of the controller, is arranged to be connected to the:control.conductor 44.

by means ofthe contacts a of the voltage relay 33, conductor 51and'the contacts a of the voltage relay 32. The circuit through the'control relay 28 is therefore completed in position VI of the controller when both of the sources A and B are energized.v The.

controller from position VI toposition I.

' From the above description it is evident that if either or both of the sources A and I Bare energized or the source C is energized. and the circult breaker'K 1S open when the I controller in position VI, the controller.

moves from this position to one of its other positions. If, however, all of the sources are not energized or the source Cfis energized andthe circult breaker K is closed the controller remains in position VI.

As the controller moves from position VI to position. I the segments on the controller connect thecont'acts13, 11,18, and 14 to the contact 27 in the order named. If both of the sources A and B are'ene'rgized so that the heretofore described circuit between the contacts 27 and the control conductor ;44 through the contacts a of the voltage relay 33,

conductor 51and contacts a of the voltage relay 32 is completed the connecting of the contacts 13, 17, 18, 20 and 14 to the contact 27 effects the closing of the circuit breakers F and G and the opening of the other circuit breakers H, J and K in a manner hereinafter described if these circuit breakers are not already in these respective positions.

The contact .13 is arranged to be connected .to the control conductor 45 by means ofzthei conductor 13, contacts met the voltage relay 33, conductor 53, auxiliary contacts {on the circuit breaker G,and 1osing coil 30 of the circuit br aker G. Therefore, if the sources A and B are energized and the aircuit breaker G is open, the closing coil 30 of the circuit breaker G is energized to close the circuit breaker when the controller moves from position VI to position I. The closing of the circuit breaker G connects the I supplementary source B'to the feeder E.

' Thecontactl? is arranged to be connected tothecontrol conductor by means of the conductor '17, contacts a of the voltage relay 32, conductor 54,-auxiliary contacts I) on the circuit breaker F and the closing coil 30 of the circuit breaker F. Therefore, if the sources A-and B are energizedand the circuit breaker F is open when the controllermoves from position VI to position I the closing coil 30 of the circuit breaker F is energized to close the circuitbreaker. I The closing of the circuit breaker F connects the preferred source A to the feeder D.

The contact 18 is arranged to be connected to the control conductor 45 by means of the conductor 18, trip coil 31 of the circuit breakerH and the auxiliary contacts a on the circuit breaker H. Therefore, if the sources A and B are energized and the circuit breaker H is closed when the controller moves from position VI to position I the trip coil 31 of the circuit breaker II is ener' gized to effect the opening'of this circuit breaker. The opening of the circuitbreaker H disconnects the two feeders D and E from each other so that only the preferred source A supplies current to the feeder Dand only the supplementary source B supplies current tothe feederE.

The contact 20 is arranged to be connected 8 to the control conductor 45 by means of conductor 20, trip coil 31 of the circuit breaker J and the auxiliary contacts aon the circuit breaker J. Therefore; if the sourcesAand B a're energized and the circuit breaker J is Y closed when the controller moves from positi'on'VI to position I, the trip coil 31 of the circuit breaker is energized to effect the opening of the circuit breaker.

The contact 14 is arranged to be connected to the control conductor 45 by means of the conductor 14,'contr0l relay 14, and the auxiliary contacts a on the circuit breaker K. Therefore, if the sources A and B are energized and the circuit breaker K is closed when the controller moves from "position VI to position, I, the control relay 14 is energized. 'The encrgization of the control relay 14 connects the trip coil 31 of thecircuit breaker K across the control circuit 44, 45, through contacts a on the circuit breaker K and conductor 67 so that the circuit breaker K opens.

From the above description, it is evident" that if the sources A and B are energized the closing of these circuithreakers so that the sources A and B are connected to the feeders Dand E, respectively, and the-energization' of the, trip coils 31' of the circuit breakers H, J and K effects the opening of these circuitbreakers so that the feeders D and E are disconnected from each other and from the source C. If, however, either one of the sources A and B is deenergizedvthe movement of the controller from position VI to position I does not effect the opening or closing of any of the circuit breakers.

As shown in the drawing, the segn'ient's on the controller 42 are so arranged that the circuits through the closing coils 3O v of the circuit breakersF and G arecornpleted before the circuits throughvthe trip coils 31 ofthe circuit breakersH, J and K arecoinpleted. Therefore, there is no interruption in the supply of current to the feedersD and E in case they" are being supplied with current when the controller moves from p'osr tion VIand the sources A and B are'enen gized. For, example, "if the source C is supplyingcurrent to the feeders D and'E through the circuit breakers KpH and J whenthe controller leaves posit on VI the sources B and A are first connected in parallel with the sourceO and then the feeders are disconnected from each other and from the source C without anyinterruption in the supply of current to either feeder. Such an arrangement, however, canonly be used where'the sources A, B and C are exactly in phase and have the same voltage, as is the case where they are supplied from a common source. WVhere the sources cannot be connected in parallel, first itis necessary to disconnect'the feeders fronrthe sources from whichthey are to be disconnected and then to connect them to the proper sources.

With such anarrangement there would be an interruption in the supply of current to a feeder whenlthe change from one source to another is taking place. Such a sequence of operation however could be obtained, if

desired, with the arrangement shown in the drawing by" merely changing the relative lengths of the segments on the controller sothat the contacts 14, 20 and 13 ar-eiconnected to the contact 2'? before the contacts 13 and 17 are connected thereto. I I

1 In position I of'the controller the segments on the controller connectthe contacts 8 and .97 together so that, if the-source A 1S energized'and the source B is de-energized,

'theheretofore described circuit between con tact 9 and the control 'conductor 44 through;

contacts f ofthe voltage relay 33, conductor 51 and contacts a of thevoltage relay-32 is completed; and if both of the sources A" and B are energized and either one of the circuit breakers F, G is open, the heretofore described circuit betweenthe contact 9"and the control conductor 44*through contacts'e of the voltage r'elay 33, conducior 52, contacts 3) of either the circuitbrea'ker F or the circuit breakerG or both, con-v ductor 51 and contacts a of the. control relay 32 is completed. Therefore, iflthe source A is energized and either the source l isv deenergized or the source B is energizcd, and either one of the circuit breakers If, Gr is open' when the controller is inpositron I, the control relay sxisene'rgized to complete the circuit ofj'the drivingniotor 43 to effect'themoveinent of the controller, from position I to position 11. 1 i

In position I the segments on the eon-3 troller also connect together the contacts 22 and 23 and thecontact 24 12 1 As heretofore described the contacts-"23 and 25'of the controllerarefconnected to.

the control bus 45 by means of the conductors ".23 and 25, respectively, which have connected in series therewith the control relays 23 and25L} The, conductor 22, which is connected to l the contact22, isarranged to be connected to'the control" conductor 44 by means of contacts f of the voltage relay 32, conductor 58 and either the contacts 0 of the voltage relay 33 or the contacts 0 of the'volt ag'e re position I, the circuit through the control lay 34. Therefore, when the controller is in i relay 23 is completed when the sourceA is deenergized and either one of the other sources isjenergizech The segments onthe controller are arranged to connect thecon tacts 22 and 23 together while the controller is inposition II and III and until it reaches position III.. Therefore, the 'energization of v the control relay under the above conditions I I efliects the movement of the controller from controller eitherwvhen both of the sources BI position I to position III.

The conductor 24, which is connected to the contact 24, has tWo branches. One of these branches is arranged to be connected to the control conductor 44 by meansof the contacts (Z of the voltage relay 33, con-' d'uctor 57 and contacts I) of tlie'voltage re-- lay The other branch is arranged to be" connected to the control conductor 44 by means. of the auxiliary contacts a on the circuit breaker F, conductor 55 and contacts I) of the underload relay 35 associated with the preferred source. A. Therefore, the cir- 1 cuitthrough the conductors 24. and 2.5 is ar ranged tobe completed in position I o'tthe and C are deenergized or when the circuit breaker F is-closed and the amount of cur; rent supplied by the source A is less than a predetermined amount which is determined by. the, setting of theunderload relay 3 5. V

From the above description, it is evident thatthe controller remains in position I only when the circuit breakers F- and G are closed, the. sources A and B are energized and-the, current supplied by the source A exceeds a predetermined value. I Asthe controller moves from position I to, position II, the segments a on the controller connect the. contacts15, 17 19, and 12. to the contacti9 in the order'nained.

. If the source A is energized and-either the source B s deenergized or the source '5 B; is, energized and either one, oi the circuit breakers F, G is open, so that the contact 9fis connectedto the'control conductor 44- the manner heretofore described, the connecting; of the contacts 15,17, I9, 20 and '12 to the contact!) effects, the closing of circuit breakersF and H, thev closing ofthe circuit breaker. K i f the source C is energized, and

the op ning of the circuit breakers Gand J ina manner hereinafter described if these circuit breakers are notalreadyin these re- Spective positions.

' The contact 15 is arranged to be connected to thecontrol coiidnctori45 by means the conductor 15, contacts. a of the voltage relay 34',' coiiductor 56, auxiliary contactsb on thefcirc'uit breaker, K and closing coil of thecircuil breaker K." Therel'orei f the con- V conductor by means of the conductor 17, contacts c of the voltage relay 32. conductor 54, auxiliary contacts 6" on the circuit tactjfQ is connected} to the control coiidu'c tor .44, thefsource C iseiiergized and the circuit a breaker K is open when the controller moves tro n position I to posit on II, the clos ng,

coil 30of the circuit breaker K isenergized to'close this circuit breaker When the controller moves fromfpositioii I to position II. Since, as heretofore described', the contact 17 isarraiigedto be connected to the control breaker F and the closing coil 30 of' the circuit breaker F, it is evident that if the con tact 9 is connected to the control conductor 44, the source 0 is energized. and the circuit breaker-F is open when the controller moves from position I to position II, the closing coil 30 of the circuit breaker F is energized to close this circuit breaker.

The contact 19 is arranged to be connected to the control conductor 45 by means otthe vconductor 19, closing coil of the circuit breaker H and auxiliary contacts. Z) on the circuit'breaker I-I. Therefore, if the contact 9 is connected to the control conductor 44 and the circuit breaker H is open when thefcontroller moves from position I to position. II the closing coil'13O of the cir' cuit breaker H is energized to ellect the closing" of this circuit breaker.

. Since, as lieretofore described, the Contact 201s arranged to be connected to thecontrol conductor. 45: by means of the conductorflt),

trip coil 310i the circuit breaker J and the auxiliary contacts on the circuit breaker 'J,.1l31S evident that if the contact 9- is con:

-Gr. ;Therefore, if the contact 9 is connected toYthecoiit-rol conductor 44 andv the circuit breaker G is closed when the controller moves from position I toposition II, the

' control relay 12 is energized. The energize.-

tion of the. control relay 12 connects the trip controlcircuit 44, 45, through contacts a" on. the circuit breaks-11G and conductor 65, so. that the circuit breaker. G opens; I

From the above description, it is evident that, if the source A is energized. and either the sourceB is .deenergized or" the source. B. is energized, and either one of. the circuit coil 31 of the circuit breaker G acrossthe llU breakers F, G is open when the l controll'er moves frompositioii I to positionj II the circuits through the closin'gcoils 30 of the circuit breakers F and II are completed, if these circuit breakers are open, tli'e circuit through the closingcoil 30"ot the circuit breaker K is completedif this circuitbreaker is open and the source C is energ'i'zedfand the circuits through the trip coils 31 of the circuit b 'eakers Gaiid J are completed if these circuit breakers are closed. The energization of theclosing coils 30 of the circuit breakers K, H 'and F effects the closing of these circuit breakers, and the energi'zation ofthe' t-rip coils 31 of. the circuit breakers G and J effects the opening of these circuit breakers, so that the preferred source A is connected to the feeder D, and if the emer-' gency source C is energized it is connected to the feeder E. I y

If, however, the contact 9 is not connected to the control conductor at, the movement of the controller from position I to position II does not effect the opening or closing of any of the circuit breakers.

I As shown in the drawing the segments on y the controller are so arranged that the circuits through the closing coils 30 of the circuit breakers K, H and F are completed before the circuits through the trip coils 31 of the circuit breakers G'and J are completed.

Therefore, there is no interruption in the supply of current to the feeders D and'E in case they are being supplied with current when the controller moves from position I. Incase it is necessary first to disconnect the feeders from the sources from which they are to be disconnected and then to connect them to the proper sources, this operation may be obtained with the arrangement shown in the drawing bymerely changing the relative lengths of the segments on the controller so that the contacts I2 and are connected to the contact 9 before the contacts 15, 17 and 1 9 are connected thereto. i In position II of the controller the segments on the controller connect together the contacts 22 and 23, so that if the source A is deenergized and either one of the other sources is energized the heretofore described circuit between the contact 22 and. the control conductor et iis completed. Therefore, the control relay 23 is energized and eifects the movement of the controller from position II to position III. V

In position II thesegments on the controller also connect together the contacts 24 and 25. Therefore, the heretofore described circuit through the control relay 25 1s com pleted inp osition II of the controller either 'when both of the sources B and. C are deenergized or when, thecircuit'breaker F is closed and the amount of current supplled by the source A is less than a predeternnned amount which is determined by the'sett ng ofthe underload relay 85. The energization ofthe controlrelay 25 under the above conditions effects the movement ofthe controller from position II to position IV. I I

In position II the segments on the controller also connect together contacts iand 5. As heretofore described the contact 51s connected to thecontrol conductor by means of the conductor 5 which has conn'e'ctedin series therewith the control relay 5.; The conductor 4 which is connected to the contact 4 has two branches. One of these branches is arrangedtohe connected to the control conductor 44 by means of the contacts 70 of the voltage relay 3 3, conductor '51 and contacts 'a of the voltagerelay 32. The other branch is arranged to be connected to thein position II of the controller when the source A is energized and either the source 13 1s energized'or the source C is energized and the circult breaker K is open. The seg- IIlGlltS on the controller are arranged to maintain the contacts 4 and 5 connected to-' gether while the controller isin positionsII and III and until it reaches-position IV. Therefore, the energization of the control relay 5 under the above conditions effects the movement of the controller from position'I to position I-V. g

From the above description it is evident that the controller remains in position II only if the circuit breakers F and K are closed, the rource B is deenergized, the sources A and C are energized andthe cur rent supplied by the source A exceeds a predetermined value. 7

As thecontroller moves from position II to positionIII, the segments on the controllerconnect the contacts 13, 15, 21, 18 and 16 to the contact 22 in the order named. If the source A is deenergized and either one-of the other sourcesis energized so that the 21, 18 and 16 to the contact 22 effects the} closing of: the circuit breaker J, the' closing of the circuit breaker G if the-source B is energized, the closing of the circuit breaker K: if the source C is energized, and the opening. of the circuit breakers Fand H in the manner hereinafter described, if these circuit breakers are not already intheserespective positionsl r Since the contact 18 is arranged to be connected to thebontrol conductor 45 by means of the conductor 13, contacts m of the voltage relay 33, conductor 53, contacts 5" on the circuit breaker G and the closing coil 30 of the circuit breaker G, it is evident that if the contact 9 is connected to the control conductor i l, the sourceB is energized,

and" the circuit breaker G is open, when the controller moves from position IIfto posi to the control conductor 4a," the source C is energized and the circuit breaker K is open when the controller moves from position II to position III, theclosingcoil 30 of the .cir cuit breaker I: is energized to eife ct the a closing of this circuit breaker when thesegments on the controller connect the contact to the contact The contact 21 is arranged to be connected to the control conductor 45 by means of the conductor 21, closing coil of the circuit breakerJ and auxiliary contacts Z) on the circuit breaker J. Therelore, 1f the conductor 22: is connected to the control con-' ductor l land the circuit breaker J is open when the controller ,moves from position II to position III, the closing. coil 30 of the circuit. breaker J is energized to close this breaker.

Since. the contact 18: is arranged to be.

. connected to thecontrol conductor 45 by means or the conductor 18, trip ,coil 31' of. the circuit breaker H and. the: auxiliary contacts a on the circuit breaker II,it is: evident thattif the conductor 221s. connected tothe control. conductor is and the circuit breaker is closed, when; the. controller. moves from position II to positionpIII, the trip col-1 31 I of thecircuit breaker H is energized to'open thiscircuit breaker: I v

The contact 16 is arranged to be connected to the control conductor 45 by means-of the conductor. 16, control relay 1 6, and auxiliary contacts-a" on the circuit breaker F. Therefore,;if t'hecontact 22 is connected to the:

' controli conductor. l4 and the circuit breaker F closed, when the controller moves from position II to position III, the control relay 16 is energized-c The energization of the control relay 16. connects the trip coil l 31. of the circuit breaker F across the con-- trol circuit 44, 45., through: auxiliary con tacts; az on the.- cir'cuit breaker F and conductor. 66., so. that the circuit. breaker F is. opened; v

sFr-om the; above: description' it. is evident.

.tliatiifthe'source A is? dcenergized either one of the oth'er sources 1s energ zed. when the controller moves from position II tov position III, the circuits throughi'the clos-' ing coils. 30 of the circuit breakers G, K and J are completed if these circuitbreakers are: open anclthe'sourcesB and Care energized, and the circuits through the tripcoils 31 of, the. circuit breakers F and H are completed if. these circuit breakers are closed. The: energization, of the closing coils 30 of the:

circuit'breakers G,K and-J cfi'ectsthe clos-' nected tothe control conductor 44, the'move ment" ofi-thecontroller from position II to position. III does not effect the opening and closing of any ofth'e circuit breakers.

As shown in the drawing, the segin'e'ntsion the controller are so arranged that the circuits through the closing coils 30 of the circuit breakers K and J are completed before the circuits through the trip coils 31 of the circuit breakers H and F are completed. Therefore, there is no interruption in the supply of currentto the feeders and E in case they are being supplied with current when the controller moves from position II. If, however, it is necessary first .ments" on the controller so that the contacts 16 and 18 are connected to the contact 22 before the contacts 13, 15 and 2 1 are connected thereto.

In position III of the controller, the segments-on the controller connect together the contacts 24' and 25 so that the liereftoforedescribed circuit through the control relay 215 is energized if both of the sources B and C aredeenergized or the circuit breaker F is closed and the amount of current supplied by the sourceA is less than a predetermined amount which isdet'ermine'd by the setting,- ofthe underload relay 35.- The energiz'ation of the control relay 25 under the above c.0nditions effects the movement of the controllerfrom position III. to position IV.

In position III the segments on thecontroller also connect together the contacts 4? and. 5 so that if thesource A is energized and either the: source B is energized or the source Cis energized and the circuit breaker K.1s open, the heretofore described circuit for; the control relay 5 is completed. The energizat-ion of thecontrol relay 5 under the above conditions effects the movement of the controller frompositionIII toposition IV.

Impos tion- III the segments on thec'ont-roller. also connect together the contacts 7v and':8.; As -heretofore described; the. contact, 81$COI1I1GC1ZBdIQ the control conductor by means otthe conductor 8 which has connected in series therewith the control relay 8, The conductor 'K which is conn'ected-to the contact? has two branches, one of which is arranged to be connected to the control conductor 44 by the-contacts bot theundere, load relay 37 and theother. of which is are, ranged to-be connected to the. control 0011-. ductor' 44- by the contactsh of .the voltage relay'33. Therefore, the circuit-through. the

' control relay 8 is arranged to be completed in position III of the controller either when the sourceiB isdeenergized or Whenthe load connec-tedto the'source C is-belowa prede to disconnect the feeders from the sources Ill termined value determined by the setting of the underload relay 37;

From :the above description it is evident,

that the controller-remains; in position III only if the source A is ,deenergized, the

, sources B and C are both energized and the troller connect the contacts 17 19,21, 12 and 14 to the contact 24 in the order named.

If the sources B and 7C are deenerglzed or the source A is energized and the current supplied thereby is less than a predetermined value, so that the contact24 is connected to the control conductor. 44in themanner heretofore described, the connecting of the'contacts '17, 19, 21, 12 and 14- to the contact 24 efl'ectsthc closing of the circuit breakers H and J, the closing of the circuit breaker F if the. source A is energizechand the opening of the circuit breakers G and K, in a manner hereinafter described, it these circuit breakers-are notialready in these respective positions. 1

Since the circuit between the'contact 17 and the control conductor is completed when the contacts cot the voltage relay 32 troller moves from positionIII: to position IV, the closing coil 30 ofthe circuit breaker F is energized to close this circuit breaker.

Since the circuit'between the contact 19.

and the control" conductor 45 is completed when the auxiliary contacts vb on the circuit breaker H are closed, it is evident that if the contact 24 is connected to the control conductor 44andthe circuit breaker H is'open when the controller moves from position III 'to' position IV,the closing coil 30 of the cir cuit breaker His energized to close this cir-.

" r the controller moves from position-III- to" position IV the circuits through the closing cuit breakerfi a 'Since the circuit between the'contact 21 and the control conductor 45 is completed when the auxiliaryucontacts Z) on the circuit breaker J are closed, it is evident that if'the contact 24 is connect-edv to the control 0011- ductor 44 and 'the circuit breaker J is open when the controller moves from position III to-position I-Vytho closingcoil 30 of the circuit breaker J is energized to close this cir cuit breaker. a r

Since the circuit betweenthe contact 12 and the control conductor 45 is completed when theauxiliary contacts a on circuit breaker. Gare closed, itis evident that if'the contact, 24 is connected to thecontrol-conductor 44 and the circuit breaker G is closed when the controller moves from position III to position IV, the control relay 12'is energized and efi'ect's the opening of the circuit breaker G in the manner heretoforeidescribed. ;.Since, the contact. 14 is connected to the control conductor 45 when the auxiliarycon- A is less than a predetermined value,-when the controller .movestrom position III to po sitionxIV, the circuits of the closing coils r30 of the circuit. breakers H and J' are com" pletedif these eircuit'breakers are open; the circuitof the closing coil :30 of the circuit breaker-F is completed if this'circuitbreaker is open and the source A is energized,and thecircuits of the trip coils 31 'ofthe-circuit breakers G and K are completed if these circuit vbreakers are closed. The energization of the closing. coils 30 of the circuit breakers F, H and J effects the closingof these circuit breakers and the energization of the trip coils 31 ofthe circuit breakersrGrand K efiects the openingof these circuit breakers so that the feeders D and E are connected together and the source A- supplies'current to both of. thesefeeders ifitis energized; a 1

1 If, however, the contact 24 is not connected to the control conductor 44 when the c'on-- the amount of current supplied by the source troller moves from position III to position IV the movement of the controller? frompo coils 30 of the circuitbreakers F, I*I and J are completed before the circuits through the trip coils 31 of the circuit breakers G and 'K are completed. Therefore, there is no interruption in the supply of current'to' the feedersD and E'in casethey are being supplied with current When the controller moves from positionIII to' positiofn IV'. If,

E however, it-isnecessary first to disconnect the feederslfrom the sources from; which they are to be disconnected, andQthen'to rangement shown in the drawing "by merely" changing the relative-lengths of the seg-- men'ts-on the controller so that thecontacts 14 and 12 are connected to the contact 24' 70 tacts a on the circuit breakerK are closed,

I Contact. l, hasfthree branches.

before the contacts 17, 19 and 21 are connectposition IV of thecontroller, the seg ments :on the-controller connect together the l contacts and 11 and the cont-acts 1 a-nd2'. .Aswheretofore described'the contacts 2 an'd 10'are connected to the control conductor by the conductors "2 and '10, respectively, which have connected in series therewith the control relays 2 and 10.

Thefioonduct-or 11 which isconnected to the contact 11 has two. branches. (he of these branches is arranged to be connected to the control conductor 44 by means -of the contacts d of the voltage relay '32, conductor 62, andithe auxiliary contacts a onthe cir 'cuitybreakerHQ The other branch of the. conductor 11 is arranged to be connected to.

the control conductor 44 by means-of the auxilia-rycontactsa' on the circuit breaker G,

conductor 63 land the contacts. bofthe um derload relay 37. -.Therefore, the control re-.

lay 10 is arranged to be energizedin-position IV of the controller either when 'thesource A is deenergized and the circuit breaker H is'closed or when fthecircuit breakerG is closed and the amount of current supplied control conductor44 by the contacts hi of i the voltagerelay 32; :5 Another one ,of these branchesis arranged to be connected to ie control conductor, 44 by. means of thecontacts e of the voltage relay 32, conductor "and either theyauxil-iary contacts Z on the circuit'breaker' H or the auxiliary contacts Z? on the circuit breaker J, orthe, auxiliary contacts b";onthecircuit breaker F Z The third branch isa rranged to be connected-to the control conductor 44 by means of thecon-;

tacts-a ofthe overload. relay 39 associated withthe source A,jcondu'ctor 58, and either the contacts C of the voltage relay 33 or the contacts 0 of the voltage relay: 34. There-- fore, the control relay 2 is arranged to be en ergized in position IV of thev controller either when the source--21 is deenergi'zed or when the source A is energized and any one of the circuit breakers H-,,J,.F is open, or When the soure -A is energized, andthej amount of current supplied thereby: is such that the overloadqrelay 39"closesits contacts a and either the source B or' the so-urceC isenergized. The; segments on the controller are arrangedto connect together the contactsi and 2 in position IV and until it reaches position V.. T herefore, the energization of the controlrelay -2 under the above conditions efi'ects the movement or t he'controller from position IV to position V.

'FI'OH] the above description, it is evident.

that the controller remains in position IV'it thesource A is energized and the circuit breakers. F, H and J are closed and the amount of current supplied'by the source A is such that the contacts a of the overload relayi39 are not closed. I

As the controller movesfrom position IV to-position V'the segments on the controller connect" the contacts13, 19, 21, 14 and 16m the contact 11 in the order named. If the nected to the control conductor. 45 when the 7 contacts m of the voltage relay 33 and the auxiliary contacts 6 on the circuit breaker" G are closed, it is evident that if the source Bis energizedand the circuit breaker G is open and the contact .11. is connected to the control conductor 44 in'the manner above described, when the controller moves from pcsition-IV 'to position V, the closing coil 30 of the circuit breaker G is energized to close thi'scircuit breakeiz.

1 Since the contact 19 is arrangedto be. con nected to the control conductor 45 when the auxiliary contacts 6 on the circuit breaker I-I are-closed, itis evident that if the circuit breaker H is open and the contact 1] is connected to;t he controlconductor 44 when the controller moves from position IV to posi--.

tion V, the closing coil 30 of the circuit-- breakenH is energized to close this breaker.

moves'froin position IV to'position V, the

closing coil 30 of 'the circuit breaker J is energizecl to close this circuit breaker.

Since the contact 14 is arrangedt'o be con nected to'the' control conductor 45 -when the contacts a on the circuit breaker K are closed, lt s evident that if the contact 11 is connected to the control conductor 44 and the circuit breaker K is closed, when the controller'moves irom'position IV to position V, the control-relay 14 is energized to reflect manner above described. Since the contact 16 18 arranged to be connected :tothe control conductor-45, when the contacts a" on the circuit breakerF are closed it is evident that it the circuit break er Fis closedand the contact 11 is connectedtothe control conductor t htvhen the circuitbreaker movesfrom position IV to position V, the control relay 16 i s energized to eifect he opening of the circuit breaker F in the dianiier above described.

From the above description, it is evident that it the 'source A is deenergized'and the circuit breaker H 'is closed,' or the circuit H 4 1 breaker G is closed, and the contactsb of the under-load relay 37are closed, when the controller moves from position; IVlto posi-' tion V, the circuits through the closing coils 230 of the circuit breakers Hand J are'com plet'ed, it these] circuit'breakers are open, the circuitthrough the'closing'coil 30 of the circuit breaker G iscoinpletcd, if this cir 1 cuit breaker is open and the source B is energized. andthe circuits through the trip coils 31 of thecircuit breakers F and K are completed, if these circuit breakers are closed.

If, however, thecontact '11 is not connected to the control conductor at the movement otthe controller from position IV to position V doesnot effect the opening and closing of any of the circuit breakers.

' As shown inthe draa-"ing, the segments on the controller are so arranged thatthe'cir cuits through the closing coils '30 of the circuitbreakers Gg'H and J are completed beforethecircuits through the trip coils 31 of the circuit breakers F and K are completed. Therefore, there'is no interruption in the supplypolt crirrentto the feeders D and E'in case they arebeing supplied with current v'fihen the controller inov'es from position It' hoiv'ever it s necessary firstto disconnect the feeders from th'e'sources from which they are to be disconnected andthen to con-' nect' them to the-proper sources illllSOPGlZt; t ion ina y'be obtained' 'vvith the arrangement shown in the drawing by merely changing the relative lengths or thefsegments on the controller so that the'contacts l6 and 14 are I connected to the contactll before the contacts 13, 19 and Qlare connected thereto;

"In position V ofthe' controller the'seg ments on the controller connect together the contacts 8 and 9 so that the heretofore described circuit through the controlrelay is energized if the source A is energized and" either" the source B is' deenergized or the sdurce B is energized and either the circuit breakcrF orthe circuit breaker 'G is open;

The energization otftlie control, relay 8 under the above cond tions-effects themovethe opening of the circuit breaker K in the ment of i the controller from position. V-toI position II. i 1 i In position V thesegments on the controller also connects together the contacts-'51 and 6 so that if the source B is energized and either the circuit breaker-f} is: open or the amount ofcurrent supplied by-the source B is such that the contacts a of theoverloada relay 40 are closed and the source C is "energized, the control relay 5' is energized and.

effects the movement of the controller from position V to position l I i y In position V the segments .on the controller also connect together the contacts 27 and 28 so that it both of the sources A and B are energized the heretofore described circuit through the control relay 28 is com-Y troller also connect together the contacts 25 and 26.= a 1 As heretofore described-the c'ontact 25 is connected to the control conductor 45 by means of the "conductor 25 which has connected in'series therewith the'control relay 25. w The cont-actQG is arranged to-be'connectcd to the control conductor 44by means of the contacts Z) of the voltage relay 33, conductor 6th and contacts b of the voltage'relay 32. 'lThereioreQthe circuit through the contacts 25 and 26 is arranged to be completed in position V ofthe controller Whcnboth of thesources B and C are c'le'energizled. From the above" descriptionyit is-ev'ident that the controller remainsin position V the source A is deenergiz'ed and the source B is energ zed and 'theamount of current supplied "bythe source B does notexceed a-predeteriiiined"value. 7 As the controllernioves from position V" to position Vl' the segmentson the controller connect thecontacts 15, 19, 21, 12 and16=to the'contact 26"in'the order named, If'both of the sources A'and B are deenergizedso that the contact-26 is connectedto"the conktrol conductor l-t the connectingof the con t'acts 15,19, 521,12 "and lti to, the contact 26 efi'ects the closing otthefcircuit breakers Hand T if these clrcuitbreakers are open; the closing of the c rcuit breaker K if this circuit breakerisopen' and the source G is energized, and the opening "ol th e circuit breakers Fandj G if these 'cir cu'i' reakers are closed. l i i Since the circuit bet'iveen the icontact 15 'andjthe control conductoree is completed vvhen the contacts a' rof'thevoltage relay andrthecontacts o onIjth-e circuit. realter It are closed, it' 'is ev dent that if the co'ntac't; 26 is connected to-[the control'conductor 4:4

and the source is energiz'edand th e c'i'rciiiu;

" sources A and B are disconnected fromth breaker F is open when the controller moves breaker.

from position V to position VI the closing coil of the circuit breaker K is energized and closes this circuit breaker.

Since the circuit betweenthe contact 19 I and the control conductor is completed when the contacts I) on the circuit breaker H are closed, it is evidentthat if the contact 26 is connected to the control conductor 44 and the circuit breaker II is open when the controller moves from position V to position VI the closing coil 30 of the circuit breaker His energized and closes the circuit breaker. Since the circuit through the contact 21 andvthecontrol conductor 45 is completed.

when thecontacts b on the circuit breaker Kare closed. it is evident that'if the contact 26'is, connected to the control conductor 44 and the circuit breaker J is open when the controller moves from position V to pos 1-.; tion VI,'the closing coil 30 of the circuit breaker J is energized and closes this circuit Since the circuit between the contact 12 and "the controllconductor 45 is completed when the contacts a on the clrcuit breakeron the circuit breaker F are closed it is evident that if the contact 26 is connected to the control conductor 44 and the circuit breaker F is open when the controller moves from position V i to position VIthe control I relay 16' is energized and effects the opening ofthe circuit breaker F in the manner above described. 1 I

" position VI does not effect the opening andv From the above description is ev dent that if both of .the sources 'A and Bare deenergized when the controller moves-from position V to position VI the circuit break;- ers H and J' are closed so that the feeders D and ,.E are connected together the circuit breakers F and G are opened so that the feeders and the circuit breaker K if the sourcev Gus energlzed. l I g If. however, the contact 261s not conis closed nccted tothe control conductor 44. the move ment of the controller from position V to closing of any of the circuit breakers. As

- shown in the drawing-thesegments on the. controller are so arranged that the circuts.

" through'theclosinq coils 30in the cir uit breakersK, H and J are completed before the circuits through theftrip coils 31 of the circuit breakers and .G are completed. Therefore there is no mte'rruption in the supply of current to the feeders in case they are being supplied with current when the controller is in position V. If however, it

from the sources from which they are ,to be disconnected, this operation may be obtained with the arrangement shown in the drawing by changing the relative lengths ofthe segments on the controller so that the contacts 12 and 16 are connected to the con tact 26 before the contacts 15, 19 and 21'are connected thereto. I

is neceisary first to disconnect the feeders As heretofore described, the controller remains in position VI when allof the sources are deenergized, and when only the source C is energized, the circuit breaker K is closed. The controller is arranged to be moved out of position VI in a manner heretofore described when either the source A or the source B. is energized or the source C is energized and the circuit breaker K is open.

From the above description, it-is apparent that the position in which'the controller 42.

stops, depends entirely upon the conditions of the sources. and of the distribution system, and that as soon as the conditions change sov that the sources should be connected tothe distributionsystem ina different combination, the controller automaticals ly moves to the position corresponding to the new cond1tions,and in so doing automaticallyconnects and disconnects the proper sources to and from the distribution system.

' The arrangementshown in Fig. 1, which comprises the :underload relays 35 and 37 for indicating when the load connected to the distribution systemis such when two sources are supplying the distribution system that one/source can supp'lyall the current without being overloaded, isssatisfactory where the ratio of the loads connected to: the two feeders:D and E is substantially constant, as is the case-where the .two feeders supply the sarne'character of load. Under these conditions the current supplied byeither source indicates approximately what the total load on the system is, so that the arrangement shown in Fig.1 is entirely satisfactory. When, howeverfthe ratio of the loadson the two feeders is subject to wide variation, the] arrangement shownin Fig. '1 is not satisfactory, because under certain conditions the underload relay associated with one of the sources might. indicate that the load cond tions were such that onesource could sup ply all of the current, whereas the load on r the othersource might'be such thatthe total load would be much more than one source could safely carry. I Therefore, the controller would operate continuously, first 'to connect bothfeeders to one source andthen' to connecteach feeder to a separate source. This cycle of operation would continue until the loadconditions changed;

In order to prevent this continuous oper .as to operate in response to the total current supplied tothe distribution system may beation of the controller under the above con ditions, a single relaywhich is connected so used instead of the underload relays and 37. Such an arrangement is shown in Fig. 3 in which the contacts 35 and the contacts 37* and 37? which are the same as the contacts controlled by the relays 35 and 37 re-' spectively, are controlled bya relay 80 which is connected in the well known manner to series transtormers'inthe supply circuits A,- B andC, so that the current through the coil ofthe relay 80 is proportional to the total current supplied at a'nyinstant to the distribution system. it-h such an arrangement, the contacts 35 37 and 37 are closed only" when the total load connected to the distribution system is less than a predeterminedvalue. l

Vhile I have shown and described oneembodiment of my invention, I do not desire to be limitedthereto, but seek to cover in the appended claims all those modifications that fall within the true spirit and scope oi my invention. i

WVhat I claim as new and desire to secure by Letters Patent of the United'states, 1s: 1. In combinatiom'a plurality of sources of current, a distribution system comprising a plurality of circuits, switching'means arrangedto connect said sources and said circuits together, means operative to effect the operation of said switching means to establishtheconnection ofall of said'circuits tonne of said sources, and means operative in response to an electrical conditlon of said systemto eflect the operation of said switching means to establish the connection of one of said circuits to a. second source and the disconnection of said one of said circuits from said first source.

'2. In combination, a plurality oit sources ofcurrent, a distribution system comprising a pl rality of circuits, switching means arranged" to connect said sourcesand sald circuits together, and means for efiectlng the operation of-said switching means to establish the connection of said one of said sources 'ineans responsive to the load on said distribution system, p

1 In combination, a source of current, a second source of current. a, distribution system comprising two distribution I circuits,

said circuits from each other.

switch-iiig neans arranged to connect said sources to said "distribution system and said circuits together, means operative in respenseto -the voltage of said firstmentioned sourcetoeffect the operation of said switching-means to establish the connection of said first'source to one of said circuits and'the connection of said circuits together, and 7 means operative in response to the load connected to said system whensaid first source is connected thereto to eifectthe operation o'f-sai'dswitching means to establish the connection of said second source to the other one oiisaid circuit-s an'dthe disconnection of saidicircuits'fro neach other. a

L- In combination, a source of current-, a secondsource of current, a distribution systenr'comprising two distribution circuits, switching means arranged-to connect said sources to said distribution system and said circuits together, means operative in response to the voltages of said sources to eifect the operation of said switching'meansto establish the connection of said first mentioned source to sneer said circuits an'dthe connection of saidcircuits'together when said first mentioned source is energizedand the connection of saidsecond "source to the other of said circuits and; the connection of said circuits together when said first source is not ener gized and said second source is energized, and means operative in response to the load connected to said. system when said first source is connected thereto to effect the op eration of said switching means to establish theconnection of said second source to said other circuit and the disconnection of 7 5.- In combination, ajsource of current, a second source'of current, a third source of current, distribution system comprising two distribution circuit-s, switching means arranged ,to connect said sources to said distribution system and said circuits together, means operative to eiiect the operation of said switching means to establish the connection of said first mentioned source to one of said circuits and the connection of said circuits together, means operative to eflectthe operation of said switching means to establish the connection of said second source to Y the" other of saidcircuits and the connection of said circuits togethenandmeans opera: tive in response "to the voltages of said sources and the load connected to said sys-c tem when said first source is connected theretoto efi'ectatheoperation of said switching means toestablish "the connection of'said third s'ource to said other one ofsaidcircuits and 'the disconnection of said circuits from each other when the load exceedsa predetermined i'value and said second source is not energized. J

6. In ct'nnbii'iation', asour'ce of current, a second source of current, a third source of current, .a distribution system comprising two distribution circuits, switching means arrangedto connect said sources to said distribution system and said circuits together, means' operative to effect the: operation of said switching means to establish the connection of said first mentioned source to one of said circuits and the connection of said circuits together, means operative toiefl'ect the operation :of said switching means toestablishthe connection of said second source? to; the other one of saidcir cuits and the connection of said circuitstogether, and means operative in responseto the voltages of said sources and the load connected to said system when said second source is connected thereto to effect the operation of said switching meansto establishthe connection of said third source to said oneofsaid circuits and the disconnection of said circuits from each other when the load'exceeds a predetermined value and said first mentioned source is not energized. 1. i i V 7. In combination, a source of current, a

7 second source of current, a third source of current, a distribution system comprising two distribution circuits, switching means arranged to connect said sources to said distribution. system and SaIdCIICUIt-S together,

' means operativein responseto the voltage of said first mentioned source to effect the operation of said switching means to establish the connection of said first sourceto one of said circuitsandthe connection of said circuits together, 'zmeans operative in responseto the load connected to said system when said first source .is connected thereto to effect the operation of said switching 'means to establish the connection of said secondsource to the other one of said circuits and the disconnection of said circuits from each other, means operative in response to the voltages of said sources and the load connected to said system when said first mentioned source is connected to said system to efl'ect the operation of said switching means to'jestablish the connection of said third source to said other one of said circuits and the disconnection of said circuits from each Y other when the loadexceeds a predetermined values and said second source is not energized, and means operative in response to the voltages ofsaid sources and the load connected to said system when said second source'is connected to said systemvto effect the" operation of said switching means to es tablish the connection of 'said third source tosaidson'e of said circuits and the disconnection ofsaid circuits from each other when the load exceeds a predetermined value and said first source is 'not energized.

8. In combination, a source of current, a second source ofcurrent, a distribution system, switching means arranged to connect said sources to said system, and means a r-r ranged to effect the-operation of said switching means. to establish the connection of .said first source to said system whenever itis energized, the connection of said second source to said system whenever said second source is energized and either said first source is not energized or said first source is energized and connected tosaid system and system is less than a predetermined amount,

said last mentioned means comprising means responsive to the respective volta es of said sources, and means responsive to t e load connected to said system.

9. In combination, a source ofcurrent,a second source of current, a third source of current, a distribution system, switching means arranged to connect said sources to i said system, and means arranged to eflect the operation of said switching means to establish the connection of said first source to said system whenever it is energized, the connection of said second source to said system whenever said sccondsource isfenergized and, either said first'source is not en-v ergized or said first source is energized and connected to said systemv andthe load connected to the system exceeds a predetermined value, the connection of said third source to sa1d system whenever said first and third sources are energized, said second source'is not energized and the load connected to said system. exceeds a predetermined value, the disconnection of each one of said sources from said system when it is connected thereto and fails, the disconnection of said second source fromsaid system whenever said second source is connected thereto said first source is energized and the load connected to said system is less than a predetermined value, and. the disconnection of said third source from said system whenever said third source is connected thereto eitherone of the other two sources is energized and the load connected to said system is lessthan a predetermined value, said last mentioned means, comprising means responsive to the respec-v tive voltages of saidsources and means resoons ve to the load connected to said, system.

10, In combination. a. source of current, a second source of current, a third source of current, a distribution system, switching means arranged to connect said sources to said system, and means arranged to effect the operation of said switching means to e tabli h the connection of said first source to said system whenever it is energized, the

lllli III] connection of said second source to said sy-s tern Whenever said second source is energized and .either's-aid first source is not'en-ergized or said first source is energized and connected to said system and the load connected to the system-exceeds a predetermined value, the connection of said third source to said system Whenever said second and third sources are energized said first source is not energized and the 'loa'd connected to said system exceeds apr'edetermined value, the'disconnection of each one of said sour from said system when it isconfnected the e to and fails. the disconnection of said'sec- 0nd source from said system whenever said second source is connected thereto said first source is energized and the load connected to said system isless than a predetermined valueyand the disconnection of said third source from'said system whenever said third source is connected thereto either one ot' the other two sources is energized and the load connected to said system is less than a'predeterminedvalue, said last mentioned means comprising means responsive to the respective voltages ofsaid sources andmeans responsive to-ythe load connected to said system. I

"11. In combination, a source of current, a-second source of current, a third source; of current, a distribution system, switching means arranged to connect-saidsources to said system, and means arranged to ettect the operation of said switching means'to establish the connection of said first source to said system whenever it is ene'rgized,-the connection of said second source to said system ivhenever said second source is energized and-either saidfirst source is not encrgized or said first source is energized and connected to said system and the load connected to the system exceeds a predetermined value, the connection of said third source to said system whenever said first and third sources are energized, said second source is not energized and the load connected to said system exceeds a predetermined-value, the disconnection of each one of'said sources from said systemwrhen it is' connected thereto and fails, the disconnection of said second source from said system "whenever said second source is connected thereto said first source is energized andthe" load connected to said systen'i is less than predetermined value, and the disconnection of said third source from said system whenever it is connected to said sys remand both ofthe other two sources are energized, said last mentioned means comprising means responsive to the respective voltages of said sources and means responsive tothe load connected to said system.

12rIn combination, a source of current. asecomlsource of current, a third so rcc o't 'current, a distribution system, switc ing meansarranged 'to connect said sources to said system, and meansarranged to efi'ect the. operation of said/switchingJmeans to minedvalue, the disconnection of each one.

of said sources from said system when it is connected thereto and fails," the disconnection of said second source'from said system whenever said second source is connected thereto said first source is energized and the load connected to said system is less than aipredetermined value, andthe disconnection otsaidfthird source from said system when-ever itI-is connected thereto and both oft'he other two sources are energized, -said lastmentioned means comprising means responsive to the respective voltages of said sources and means-responsive to the'iload connected-to said system.

s '13. In combination, a source of current, a 7

second sourceotcurrent, a, distribution system comprising two distribution circuits, switching means arrangedto connect said sources to said distribution system and said circuits together, means arranged to efiect the operation of, said switching meansto establish theconnection of said :first source to one of; said circuits, the connection o f s aid circuits together and the disconnection of said second source from said system whenever said first source is energized and the load connected to said system is less than a predetermined value the connection of said second source. tothe other one ofhsaid circuits, the connection of said circuits together and the disconnection of said first source from said one of saidcircuits whenever said first source s not energized, said second source is energized and theload connected to said system isless than a predetermined value, and the connect on of saidfirst source to said one; of said circuits, the connection.

ofsaid secon'dsourceto said other one of sa d circu ts and the disconnection of, said circu ts from eachother wheneversaid first and secondsoui 'ces are energized"and, the.

load connected to said jsystemexc'ee' ds api determined value, said last nentionedineans comprising means responsive to therespec tive voltages of said'sources, and means ,re sponsive to "the load connected to] aid, s s m- I 14L. In combination, a' gourmet current, 'a

M secondsource of'current, a third source of current, a distribution system comprising two circuits, switching means arranged'to connect said sources to said distribution systemandsaid circuits together, means arranged to effect the operation of said switching means to establish the connection of said first mentioned source to one of said circuits,

the connection of said circuits together and the disconnection of said second source from said system whenever said first source is energized and the load connected to said system is less than a predetermined value; the" said circuits from each other Whenever saidfirst and second sources are energized and the load connected to said system exceeds a predetermined value, and the connection of sources from saidsystem when said first and second sources are not energized and said third source is'energized, said last mentioned means comprising means responsive to the respective voltages ofsaid sources and means responsive to the load connected to said system. V

' 15. In combination, a source of current, a second source of current, athird source of current,*a distribution system compr sing two circuits, switching means arranged to connect said sources'to'said distribution sys-' tem and said circuits together, meansarranged to effectthe operation of said switching means to cstablishthe connection vof said first source to one of'said circuits, the con- 'nection of said circuits together and the disconnection'of said second source from said system whenever said first source is energized and the load connected to said system is less than a predetermined value; the connect-ion of said second source to the other one of said circuits, the connection of said circuits together and the disconnection of said fiistsource. from said one of said circuits whenever said first source is not energized, said second source is energized and the load connected to said system is less than-a predetermined value, the connection of said first source to said one of said circuits, the connection of saidsecond source to said other (m et. said circuits and the disconnection of said circuits from each other Whenever 7 said first and second sources are energized said third source to both of said circuits and the'disconnection of said first and second I and the load connected to said system exceeds a predetermined value,-and the connection of said third sourc-e'to said one of said circuits, the connection of isaidlsecondsource to said other one of said circuits, the

source is not energized, said second and third sources are energized and the load connected to saidsystem exceeds a predetermined. value, said last mentioned means comprisingmeans responsive to the respective voltages of said sources, and means responsive to the load connected to said system.

16. In combination, a source of current, a second source of current, a third source of current, a distribution system, comprisingtwo circuits, switching means ar'rangedto connect said sources to said distribution system and said circuits together, means ar-v ranged to effect the operation of said switching means to establish the connection of said first source to one of said circuits, the connection of said circuits together, and the discone ncctioii of said second source from said system, wheneverv said first sourceiis energized and the ioad connected to said system isless than a predetermined value, the connection of said second source to the other one of said circuits, the connection of said circuits to-v gether and the, disconnection of said first source from said one of said circuits whenever said first sourceis not energized, said secondsource is energized and the load connected tofsaid system is less than a predetermined value, theconnection ofsaid first source'to said one of said circuits, the connection of said second source to said other one of said circuits and the disconnection ,of said circuits from each, other Whenever said first and second sources are energized and the load connected to said system exceeds a predetermined value, and the connectionof saidthird source to said other one of said circuits, the connection of said first source to said one of said circuits, the disconnection of said circuits from each other, and the disconnection or" said second source from said system whenever said second source-is not energized, said first and third'sources are energized, and the load on said system ex: ceeds a predetermined value, said last men: tionednieans comprising means responsive to the respective voltages {of said sources, and meansresponsive to the load connected to said system. y 7

17. In combination, a plurality of sources of current, a distribution system comprising two circuits, switching means arranged to connect saidsources to said system andsaid circuits together, and-'means arranged to effect the operation of said switchingmeans to establish the connection of vone of said sources to one of said circuits, the connec hit] energized or said first source is not energized and the load connected to said system is less thana predetermined value, said last men-- tioned means comprising means responsive to the, respective voltages of said sources, and means responsive to the load connected to said system. a I

18. In combination, a plurality of sources of current, a distribution system comprising two circuits, switching-means arranged to connectsaid sources to said system and said circuits together, and means arranged to effect the operation of said switching means to establish the-connection of one of said sources to one of said circuits, the connection of said circuits together and the disconnection of all of the other sources from said system whenever said one source is energized and either all of the other sources are not energized or-the load connected to said system is less than a predetermined value, the

connection of a second source to the other one of said circuits and the connection of 5311C]. circuits together whenever said second source is energized'and either all of the other sources are not energized or said one source is not energized and the load connected to said system 13' less than a predetermined value, the connection of a third source to said one of said circuits. the connection of said circuits together and the disconnection-of said one and second sources from said system whenever said one and second sources are not venergized and said third source is energized, the connection of said third source to said one of said circuits, the connection of said second source to said other one of said circuits, and the disconnection of said circuits from each other and of said one source from said system whenever said one source is not energized, said second and third sources are energized and the load on said system exceeds a predetermined value,'and the connection of said third source to said other one of said circuits, the connection of said one source to said one of said circuits, and the disconnection of said circuits from each other and of said second source 'from said system whenever said one and third sources are energized,.said second source is not energizedand the load connected to said system exceeds a predetermined value, said last mentioned means comprising means re sponsi've to the respective voltages of said sources and means responsive to the load "connected to said system.

19. In combination, a source of current, a

second source of current, a third source of current, a distribution system, switching means arranged to connect said sourcesto said system and means arranged to effect the operation of said switching means to establish the connectionof said first mentioned source to said distribution system whenever said first source is energized, the connection of said second source to said distribution system whenever said first source is not energized and said second source is energized, and the connection of said third source-to said distribution system whenever said-third source is energized and the other two sources are not energized, said last mentioned means comprising means responsive to the respective voltages of said sources, and means for automatically controlling the sequence of operation of said switching means.

20. In combination, a source of current, a second source of current, a third sourceof current, a distribution system, switching means arranged to, connect said sources to theoperation of said switching means to establish the connection of said first mentioned source to said distribution system when said first source is energized, the disconnection of said first source fromsaid distribution system when; said source fails, the

connection of said second sourceto said distribution system when said first, source is not energizedand said second source is energized, the disconnection of said second sourcefrom saiddistribution system when said second source fails or said first source ,is energized, the connection of said third source to said distribution system when said first source fails said second source is not energized and said third source is energized, and the disconnection of said third source from said distribution systemavhen either one or said other sources is energized or said third source fails, said last mentioned means comprising means responsive to the voltages of said sources, and 'means for automatically controlling the sequence of operation of said switching means,v

21. In combination, a plurality of sources ofcurrent, a distribution system comprising a plurality of circuits, switching means arranged to connect said sources and said circuits together, and means arranged to effect the operation of said switching means to establish the connection of one of said sources to all of said circuits of said sys tem when said onevof said sources is energized and the load connected to said system does not exceed a predetermined valueand to eti'ect the disconnection of some of said circuits from said one of said uesses, the connection of said disconnected circuits .said system, and means arranged to efiect v to another one of said sources when the load connected to said system exceeds a predetermined value, said last mentioned means comprising means responsive to the relative voltages of said sources, means responsive t'othe' load connected to said distribution system, and means for automatically controlling the sequence of operation of said switching means.

"22. 'In combination, a source of current, a second source of current, a distribution system comprising two distribution circuits, switching means arranged to connect said sources to said distribution system and said circuits together, means arranged to effect the operation of said switching'means to establisl'i' the connection of said first source to one of said circuits, the connection of said circuits together and the dis connection of said second source from said systemwhenever said first source is energized and the load connected to said system "is less than a predetermined value, the connection of said second source to the other one ofsaid circuits, the connection of said circuits together and the disconnection of said first source from said one'of said circuits Whenever said first source is not energized, said second source is energized and the load connected to said system is less than a predetermined value, and the connection of said firstsource to said one of said circuits, the connection of said second source to said other one of said circuits and the -disconnection' of said circuits from each' other Whenever said first andsecond sources are energized and the load connected to said system exceeds a predetermined value, said last mentioned means comprising means responsive to the relative voltages of said sources, means responsive to the load connected? to said distribution system, and means for automatically controllingthe sequenceof operation of'said switching means.

23. In combination, a plurality of sources ofourrent, a distribution system comprising two circuits, switching means arranged to connect said sources to said system and said circuits together, and means arranged to eflect the operation of saidswitching' means to establish the connection of one of said sources to one of'said circuits, the connection ot said circuits together and the disconnection of all of the other sources'from said system whenever said one source is energized and either all of the other sources are not energized or the load connected to said system is less than a predetermined.

tritium-theconnectionof a second source to theother one ofsaid circuits and the con.- neictaon of sa d circuits together whenever said second source is energized and either all ofthe' other sources are notenergized'or said'one source is'not energized and theload connected tosaid system is less than a predeterminedvalue/the connection of a third source to said one of said circuits, the connection ofsaid circuits together and the'disconnection of said one and second sources irom said system whenever said one and second sources are not energized and said third source is energized, the connection of said third source to said one of said circuits, the connection of said second source to said other one o'f-said circuits, and the discoiinecti'on. of said circuits from each other and of said one source from said system whenever said one source is not energized, said second and third sources are energized and the load on said system exceeds a predetermined value, and the connection of said third source to said other one of said circuits, the connection of said one source to said one of said circuits, and the disconnection of said circuits from each other and of said second source from said system whenever said one and third sources are energized, said second source is not energized and the load connected to said systemexceedsa predetermined value, said last mentioned means com-' prising means responsive to the relative voltages of said sources, means responsive to the load connected to said distribution system, and means for automatically controlling the sequence of operation 0t" said switching means.

24. An electric system comprising a source of current, a second source of current, a

' third source of current, a distribution system, switching means arranged to connect each source to said distributionsystem, and means arranged to effect the connection 0t saidfirst mentioned source to said distribution system whenever said first mentioned source is energized, the connection of said switching means.

. 25. An electric system comprising a'sourceof current, a second source of current, a? third source .ot current, a distribution system, switching means arranged to connect each source to. said distribution system, means arranged to efiect the connection of said first mentioned source to said distribution system when said first source is energized, the disconnection of said first source from said distribution system when said source fails, the connection of said second source to said dis- 

